Requirement Of Anesthetic Agents Research Articles

Use of Dexmedetomidine versus Nitroglycerine to Provide Hypotensive Anesthesia in ENT Surgeries (Functional Endoscopic Sinus Surgery)

Abstract Background controlled (deliberate/induced) hypotension is a technique by which the arterial blood pressure is lowered in a controllable manner to reduce surgical blood loss and improve the operative field visibility. There are pharmacological and nonpharmacological techniques for inducing hypotension. The nonpharmacological methods for deliberate hypotension include positioning and positive pressure ventilation to control venous return. Aim of the Work to evaluate the efficacy of dexmedetomidine (DEX) as a hypotensive agent in comparison to nitroglycerin (NTG) in FESS regarding the bloodless field, reduction of mean arterial blood pressure, decrease inhalational anesthetic requirements (MAC), decrease perioperative opioid requirements, increase the time to first postoperative analgesic request and recovery profile and increase hemodynamics stability. Patients and Methods we conducted this study on 20 patients who were planned to perform functional endoscopic sinus surgery and were randomly distributed into 2 equal groups: 10 patients received dexamedotomidine and equal number of patients received nitroglycerine. Serial measurements of mean arterial blood pressure and heart rate were obtained and records between both groups were compared. Results There were statistically significant differences between both groups regarding heart rate as mean values of heart rate were lower among dexamedotomidine group. There were no statistically significant differences between both groups regarding mean arterial blood pressure values at different time points during the operation. Regarding the period after stopping infusion, mean values of heart rate and blood pressure were lower among dexamedotomidine group than nitroglycerine group after 5 minutes and after 10 minutes and the differences had statistically significant differences. Regarding postoperative period, both groups were comparable regarding heart rate and blood pressure immediately postoperative. Conclusion From the results of this study, we could conclude that both Dexmedetomidine and Nitroglycerin can be effectively used in induced hypotensive anesthesia for ENT surgery as FESS. Both groups were comparable with intra operative MAP with no statistically significant differences. This study also show that Dexmedetomidine has added advantages as better haemodynamic stability than Nitroglycerin (No rebound HTN, no tachycardia). Has sedative and analgesic effect, reduce requirement of anesthetic agents and perioperative analgesia. Postoperative recovery score (Time to reach modified Aldert score more than nine significantly higher. Postoperative complication as nausea and vomiting is less.

A randomized comparative study of preoperative fentanyl and dexmedetomidine nebulization on the hemodynamic response to endotracheal intubation

Background: Intense sympathetic activity is linked to laryngoscopy and endotracheal intubation, which could lead to intraoperative problems. We undertook this study to compare the effects of preoperative nebulized Fentanyl and Dexmedetomidine on hemodynamic response to laryngoscopy and endotracheal intubation, taking advantage of their high bioavailability and better absorption through nasal mucosa. Aim and Objectives: The objectives of the study were (i) to compare the effect of preoperative nebulization on the hemodynamic response to laryngoscopy and intubation; and (ii) to assess intraoperative requirement of anesthetic agents. Materials and Methods: This prospective, randomized, and comparative study was conducted among 100 American Society of Anesthesiologists (ASA) I, II patients (of either gender) undergoing elective surgeries and requiring tracheal intubation, were randomized in two groups. Group A was given Fentanyl Nebulization (2 μg/kg in 4 ml of 0.9% saline) and Group B was given Dexmedetomidine nebulization (1 μg/kg in 4 ml of 0.9% saline) 10 min before anesthesia induction. Hemodynamic parameters were noted before and immediately after induction, 1 min, 5 min and 10 min after intubation. The main goal was to assess how Fentanyl and dexmedetomidine nebulization affect the laryngoscopy and intubation-induced stress response. The secondary outcome was to assess the intraoperative requirement of anesthetic agents, observe adverse effects of study drug and sedation score. Results: Dexmedetomidine nebulization was found to be more effective in blunting rise in heart rate post laryngoscopy compared to Fentanyl Nebulization (P < 0.0001) as well as in MAP after 10 min of intubation (P < 0.0001). Requirement of propofol was seen to be significantly reduced in Group B compared to Group A (P < 0.05). Sedation scores were significantly higher in Group B (P < 0.05). No evidence of side effects was observed in any group. Conclusion: Nebulisation of dexmedetomidine was found to be more effective in attenuation of stress response of laryngoscopy and intubation compared to nebulisation of fentanyl, with stable intraoperative hemodynamic and no significant side effects.

Usefulness of supplemental parasternal block for sternal keloid excision under general anesthesia in a child status post multiple cardiac surgeries

Sir A 12-year-old boy weighing 60 kg, with history of tricuspid atresia, had undergone right modified Blalock–Thomas–Taussig shunt, and patent ductus arteriosus ligation on day 1 of life. One year later he underwent bidirectional Glenn shunt, and extra cardiac Fontan surgery was done at 6 years. He presented now with a thick keloid in the midline sternotomy scar for keloid excision. Current screening echo showed tricuspid atresia, normally related great arteries with normal ventricular flow and unobstructed Glenn and Fontan flow profiles. Intravenous midazolam 1 mg, fentanyl 100 mcg and ketamin 60 mg were given and incremental bolus of propofol 10 mg (total 20 mg) was given till loss of response to verbal commands and relaxation of jaw. Airway was then secured with size 3 proseal laryngeal mask airway (PLMA) and correct placement was ensured with regular endtidal carbon dioxide (ETCO2) waveforms. Parasternal block was then given under ultrasound guidance at third and fifth intercostal spaces 2 cm lateral to midline bilaterally. Spread of injected solution causing separation of pectoralis major muscle from the rib and external intercostal muscle confirmed deposition of drug in the correct plane (Fig. 1). Ten milliliter of 0.25% bupivacaine was injected at each site.Figure 1: Superficial parasternal-intercostal plane block.Anesthesia was maintained with sevoflurane (1.5–2%) in air oxygen mixture under spontaneous ventilation. Intraoperatively patient remained stable with heart rate 86-98/min, systolic blood pressure 90–100 mmHg, oxygen saturation 96–98% and ETCO2 32-40 mmHg and had received 500 ml of Ringer lactate. At the end of surgery, which lasted for 2 h, PLMA was removed when patient was awake. He had good postoperative analgesia. Anesthetic goals in a child post-Fontan surgery include adequate hydration, avoidance of hypoxia, hypercabia, and acidosis and preservation of spontaneous ventilation whenever possible. If general anesthesia is mandated, low inspiratory pressures and minimal positive end expiratory pressures are to be used [1,2]. Sternotomy produces considerable pain which increases with chest wall movement and reduces pulmonary function with higher risk of development of postoperative hypoxia, atelectasis, and pneumonia [3]. Parasternal block is commonly advocated to provide supplemental anaesthesia intraoperatively and for postoperative analgesia following median sternotomy, breast surgery and cardioverter-defibrillator implantation [4,5]. The nerve targeted is the anterior branches of intercostal nerves which enters intercostal and pectoralis major muscles and innervates the antero-medial region of chest wall. Local anesthetic is injected deep to pectoralis major muscle and superficial to intercostal muscles or between internal thoracic muscle and transverses thoracis muscle. Therefore, these blocks are essentially described as superficial or deep parasternal-intercostal plane blocks, depending on where the target nerves are blocked. The anatomical injection site differentiates these techniques though both techniques provide analgesia to the antero-medial chest wall [5]. Supplemental regional block helps to reduce dose requirement of anesthetic agents intraoperatively. Use of supplemental parasternal block enabled us to keep the child spontaneously breathing under general anaesthesia using PLMA with use of lesser doses of anesthetic agents, thereby minimising drug adverse effects which could be deleterious in the presence of cardiac diseases. It is concluded that supplemental parasternal block provides good intraoperative and postoperative analgesia following anterior midline chest wall surgeries.

Comparison of recovery profiles of propofol and sevoflurane anesthesia with bispectral Index monitoring In general anesthesia: Running title: Recovery profiles: Propofol vs sevoflurane

Introduction: Introduction of more rapid and short-acting volatile anesthetics and intravenous anesthetics has allowed anesthesiologists to achieve a recovery profile that facilitates rapid emergence after general anesthesia. Both propofol and sevoflurane provide rapid induction and faster recovery by titrating the depth of anesthesia based on the BIS Index during maintenance. The objectives of the study were analysis of hemodynamic parameters, changes in the BIS Index, recovery characteristics, postoperative complications. Methods: Following IRB approval, an observational study was conducted in 60 patients of ASA grade I-II, aged 18-60 years undergoing surgical procedures under general anesthesia. Patients were randomly divided into two groups, with 30 patients each receiving propofol infusion (Group P) or sevoflurane (Group S) to maintain anesthesia. The requirement of anesthetic agents was titrated by BIS monitoring. BIS score was held between 40 to 60. Results: Hemodynamic parameters like heart rate and mean arterial pressure (MAP) were comparable in both groups. During recovery, the meantime to spontaneous ventilation, eye-opening, hand squeezing, following verbal command, extubation, stating the name, and mean time to achieve modified Aldrete's score of ≥ 9 from the cessation of the anesthetic drug was significantly shorter in Group S as compared to Group P. PONV was noted as a postoperative complication in the sevoflurane group. Conclusion: In our study, sevoflurane provided rapid emergence and faster recovery with stable hemodynamic. However, propofol appears to be an excellent alternative to sevoflurane for maintenance of anesthesia as it also provides fast recovery with a lower incidence of PONV

A comparative evaluation of epidural clonidine vs. dexmedetomidine as adjuvants in post-operative analgesia

Background: Requirement of anesthetic agents is reduced due to addition of adjuvants in epidural anaesthesia as they augment the local anesthetic action and have analgesic properties as well. Effective epidural analgesia ensures stable hemodynamics and satisfactory perioperative period. Objective: To evaluate efficacy of epidural clonidine compared to dexmedetomidine as adjuvants in postoperative analgesia Materials and Methods: Comparative, randomized clinical study was carried out among 100 subjects undergoing abdominal and vaginal hysterectomies of age 44-65 years with ASA grade I and II. They were divided randomly into two group of 50 each. Group A received 17ml of 0.5% of bupivacaine with 2mcg per kg clonidine. Group B received 17ml of 0.5% of bupivacaine with 1.5mcg per kg dexmedetomidine. Various parameters related to sensory and motor blockade, Ramsay sedation scale for sedation score, Hemodynamic parameters were monitored continuously and recordings were made at regular intervals. Results: Both groups were comparable in terms of age, weight, duration of surgery, ASA grades and type of surgery. Parameters pertaining to time for onset of sensory and motor block were significantly higher in clonidine group compared to the dexmedetomidine group (p0.05) between two groups except for heart rate which was significantly less in dexmedetomidine group at 120min compared to clonidine group (p Conclusion: Dexmedetomidine added to bupivacaine epidurally prolonged postoperative analgesia longer than clonidine. Keywords: Dexmedetomidine, Clonidine, Bupivacaine, Epidural.

Clinical Assessment of an Ipsilateral Cervical Spinal Nerve Block for Prosthetic Laryngoplasty in Anesthetized Horses.

The nociceptive blockade of locoregional anesthesia prior to surgical stimulation can decrease anesthetic agent requirement and thereby potential dose-dependent side effects. The use of an ipsilateral second and third cervical spinal nerve locoregional anesthetic block for prosthetic laryngoplasty in the anesthetized horses has yet to be described. Anesthetic records of 20 horses receiving locoregional anesthesia prior to laryngoplasty were reviewed and compared to 20 horses of a similar patient cohort not receiving locoregional anesthesia. Non-blocked horses were 11 times more likely to require adjunct anesthetic treatment during surgical stimulation (P = 0.03) and were 7.4 times more likely to receive partial intravenous anesthesia in addition to inhalant anesthesia (P = 0.01). No horse in the blocked group received additional sedation/analgesia compared to the majority of non-blocked horses (75%) based on the anesthetist's perception of anesthetic quality and early recovery movement. No difference in recovery quality was observed between groups (P > 0.99). Cervical spinal nerve locoregional anesthesia appears well-tolerated and useful in reducing cumulative anesthetic agent requirement and may decrease the need for additional sedation/analgesia in horses undergoing anesthetized prosthetic laryngoplasty.

Preliminary investigation of preoperative pregabalin and total intravenous anesthesia doses: a randomized controlled trial

Study objectiveTo determine the efficacy of 2 different doses (150-300mg) of preoperative pregabalin on propofol and remifentanil doses for total intravenous anesthesia in laparoscopic cholecystectomy. DesignProspective, randomized, placebo-controlled, double-blinded study. SettingTraining and research hospital. PatientsForty-eight adult, American Society of Anesthesiologists physical status 1 and 2 patients. InterventionsPatients were randomly assigned to 3 groups to receive orally 1hour before surgery, a placebo group (group 1), pregabalin 150mg (group 2), or pregabalin 300mg (group 3). MeasurementsIn the operating room, heart rate, systolic and diastolic blood pressures, SpO2, bispectral index, and body temperature were recorded just before anesthesia induction; 1 and 5minutes after induction; and at minutes 10, 15, 20, 25, 30, 35, and 40 of the surgery. Required propofol and remifentanil doses to obtain bispectral index value less than 60 were also recorded. Main ResultsThe remifentanil doses used in the pregabalin groups at minutes 10, 15, 20, 25, and 30 and propofol doses at minutes 15, 20, 25, and 30 were statistically significantly lower in comparison to the placebo group. ConclusionThe observations provide preliminary evidence that preoperative pregabalin may decrease anesthetic agent requirement in total intravenous anesthesia patients.

Comparative Evaluation of Dexmedetomidine and Magnesium Sulphate on Propofol Consumption, Haemodynamics and Postoperative Recovery in Spine Surgery: A Prospective, Randomized, Placebo Controlled, Double-blind Study.

Dexmedetomidine and magnesium sulfate have been used in anesthesia as adjuvant to provide hemodynamic stability and anesthetic agents sparing effect. We compared these effects of dexmedetomidine and magnesium sulfate in spine surgeries. Ninety patients were randomly assigned to three groups. Group D received dexmedetomidine loading dose 1 µg/kg over a period of 15 minutes and maintenance 0.5 µg/kg/h throughout the surgery. Group M received magnesium sulfate loading dose 50 mg/kg over a period of 15 minutes and maintenance 15 mg/kg/h throughout the surgery. Group C received same volume of normal saline. Heart rate (HR) and blood pressure values were recorded at various intervals. The induction and maintenance doses of anesthetics and recovery parameters were also recorded. Heart rate in group D and group M were significantly decreased (p<0.05) during the whole intraoperative period compared to preoperative values. There was a significant difference in HR values between group C, D and M, during the whole intraoperaive period (p<0.05). Blood pressure values were statistically significantly lower in the group D and group M compared to group C after intubation and all time observations of surgery (p<0.05). Both drugs reduced the anesthetic agent's requirement during surgery. However, the recovery parameters were statistically significant increase with magnesium sulphate compared to dexmedetomidine and control groups. Dexmedetomidine is more effective than magnesium sulfate for maintaining the hemodynamic stability in spine surgeries. Both these drugs also reduce the requirements of anesthetic agents. Recovery from dexmedetomidine is as rapid as control group compared to magnesium sulfate.

Minimum alveolar concentration of desflurane with caudal analgesia for laryngeal mask airway removal in anesthetized children

Regional blocks have been shown to decrease the requirement of anesthetic agents. This study was conducted to determine the optimal endtidal concentrations of desflurane for removal of Laryngeal mask airway in children in presence of caudal block. Twenty-two children of ASA status I between the age group of 2-10 year undergoing infraumbilical surgery were enrolled in the study. General anesthesia was induced with sevoflurane and oxygen given via mask and laryngeal mask airway inserted. Caudal injection of bupivacaine 0.25%, 1 ml·kg(-1) was administered according to Armitage regimen. Desflurane was used for maintenance of anesthesia. Predecided endtidal concentration of desflurane was maintained for 10 min at the end of surgery and laryngeal mask airway removed. Target concentration in the next patient was thereafter determined by the Dixon up-down method (with 0.5% as a step size). 5% endtidal concentration was kept as the starting concentration. If removal of laryngeal mask airway was not associated with any coughing, teeth clenching, gross purposeful movement, breath holding or laryngospasm, during or within 1 min after removal, it was considered as successful. In the presence of caudal analgesia, endtidal concentration of desflurane required for successful laryngeal mask airway removal in 50% (ED50) children was 3.39 ± 0.38% by Dixon's method. Laryngeal mask airway can be successfully removed in 50% of anesthetized children without coughing, moving, or any other airway complications at an endtidal desflurane concentration of 3.4% in the presence of caudal analgesia.

Femoral and sciatic nerve block with 0.25% bupivacaine for surgical management of diabetic foot syndrome: an anesthetic technique for high-risk patients with diabetic nephropathy

A case series of patients with diabetic nephropathy, who underwent lower limb debridement or amputation below the knee during successful combined sciatic and femoral nerve block with bupivacaine 0.25%, is presented. Because impaired nerve conduction in diabetes mellitus results in lower local anesthetic agent requirement, a dose-sparing, minimal effective concentration for surgical anesthesia for peripheral nerve blockade may be more favorable for patients with diabetes and chronic renal disease.

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children

BackgroundAn anesthetic state can reduce adverse airway reaction during laryngeal mask airway (LMA) removal in children. However, the anesthetic state has risks of upper airway obstruction or delayed emergence; so possibly less anesthetic depth is advisable. Caudal analgesia reduces the requirement of anesthetic agents for sedation or anesthesia; it is expected to reduce the sevoflurane requirement for LMA removal. Therefore, we determined the EC50 of sevoflurane for LMA removal with caudal analgesia and compared that to the EC50 without caudal analgesia.MethodsForty-three unpremedicated children aged 1 to 6 yr were enrolled. They were allocated to receive or not to receive caudal block according to their parents' consent. General anesthesia were induced and maintained with sevoflurane and oxygen in air. EC50 of sevoflurane for a smooth LMA removal with and without caudal analgesia were estimated by the Dixon up-and-down method. The LMA was removed when predetermined end-tidal sevoflurane concentration was achieved, and the sevoflurane concentration of a subsequent patient was determined by the success or failure of the previous patient with 0.2% as the step size; success was defined by the absence of an adverse airway reaction during and after LMA removal. EC50 of sevoflurane with caudal block, and that without caudal block, were compared by a rank-sum test.ResultsThe EC50 of sevoflurane to achieve successful LMA removal in children with caudal block was 1.47%; 1.81% without caudal block. The EC50 were significantly different between the two groups (P < 0.001).ConclusionsCaudal analgesia significantly reduced the sevoflurane concentration for a smooth LMA removal in anesthetized children.

Individualized Feedback of Volatile Agent Use Reduces Fresh Gas Flow Rate, but Fails to Favorably Affect Agent Choice

Cost reduction has become an important fiscal aim of many hospitals and anesthetic departments, despite its inherent limitations. Volatile anesthetic agents are some of the few drugs that are amenable to such treatment because fresh gas flow rate (FGFR) can be independent of patient volatile anesthetic agent requirement. FGFR and drug use were recorded at the temporal midpoint of 2,031 general anesthetics during a 2-month preintervention period. Staff and residents were provided with their preintervention individual mean FGFR, their peer group mean, and educational material regarding volatile agent costs and low-flow anesthesia. FGFR and drug use were remeasured over a 2-month period (postintervention) immediately after this information (N = 2,242) and again 5 months later (delayed follow-up), for a further 2-month period (N = 2,056). For all cases, FGFR decreased from 2.4+/-1.1 to 1.8+/-1.0 l/min (26% reduction) after the intervention and increased to 1.9+/-1.1 l/min (5% increase of preintervention FGFR) at the time of delayed follow-up. Use of more expensive volatile agents (desflurane and sevoflurane) increased during the study period (P < 0.01). In a subgroup of 44 staff members with more than five cases in all study periods, 42 members decreased their mean FGFR after intervention. At delayed follow-up, 30 members had increased their FGFR above postintervention FGFR but below their initial FGFR. After accounting for other predictors of FGFR, the effectiveness of the intervention was significantly reduced at follow-up (28% reduction), but retained a significant effect compared to preintervention FGFR (19% reduction). Although individual feedback and education regarding volatile agent use was effective at reducing FGFR, effectiveness was reduced without continued feedback. Use of more expensive volatile agents was not reduced by education regarding drug cost, and actually increased.